Study of Virus is known as Virology. Virus is noncellular. Virus is non living and living both. In inert condition it is non living but whenever it comes in contact with organism it multiplies and shows living phase.It is connecting link between non living and living. Viruses are visible only under electronmicroscope. American microbiologist W.M. Stanley is known as Father of virology. In virus either DNA or RNA is present. Virus is living as it shows growth on contact with living organism. A protective sheath is present known as Capsid made up of protein. Capsid is formed by numerous protein molecules known as Capsomeres. Each particle consists of a single coiled filamentous molecule of DNA or RNA.Viruses are spread by Insects, air, cough, sneeze and excreta. Viruses dissolve membrane of host cells by enzyme neuraminidase & some enter by phagocytosis & some by fusion.
Viruses causing important diseases:
(1)Influenza – Paramyxo virus -> RNA
(2) Small pox – Variolla virus -> DNA
(3) Measles – Paramyxo virus -> RNA
(4) Polio – Entero virus -> RNA
(5) German measels (Rubella) – Tago virus -> RNA
(6) Cold – Orthomyxo virus -> RNA
(7) Chicken pox – Varicella virus -> DNA
(8) Mumps – Paramyxo virus -> RNA
(9) Rabies – Rhabdo virus -> RNA
Examples of smallest and largest viruses:
Smallest virus = virus of mouth disease 15 µm.
Largest virus = virus of parrot fever 450 µm.
Who discovered Polio vaccine?
John Salk 1st discovered Polio vaccine.
Who discovered small pox vaccine?
Edward Jenner 1st discovered small pox vaccine.
Who discovered preventive treatment against Rabies?
Louis pasteur 1st discovered prevention treatment against Rabies.